LADSPAStream: fixed input port mapping

 * User-provided arguments should correspond to the n'th input port
   instead of the n'th overall port.
   This failed if output ports were mixed with input ports (or come first)
   in the list of ports that the LADSPA plugin defines.

1 files changed, 4 insertions, 1 deletions

diff --git a/ladspa.lua b/ladspa.lua
index b6af57e..3c207e8 100644
--- a/ladspa.lua
+++ b/ladspa.lua
@@ -257,16 +257,19 @@ function LADSPAStream:ctor(file, ...)
 	-- List of output port numbers (origin 0)
 	self.output_ports = {}
 
+	local input_port_count = 0
 	for i = 0, tonumber(self.descriptor.PortCount)-1 do
 		local port_descriptor = self.descriptor.PortDescriptors[i]
 
 		if bit.band(port_descriptor, ffi.C.LADSPA_PORT_INPUT) ~= 0 then
+			input_port_count = input_port_count + 1
+
 			local port_name = ffi.string(self.descriptor.PortNames[i])
 
 			-- We must connect all ports, so if the user does not provide
 			-- an input stream or constant, we try to provide a default.
 			-- There may be no default, in which case we throw an error.
-			local data = input_ports[i+1] or input_ports[port_name] or
+			local data = input_ports[input_port_count] or input_ports[port_name] or
 			             getPortDefault(self.descriptor.PortRangeHints[i]) or
 			             error('Input stream/constant for port "'..port_name..'" in plugin '..
 			                   '"'..file..'" required')